Phosphatidylethanol (PEth) has gained special attention as a marker of long-term alcohol drinking. Current methods of analysis of PEth are based on the high performance liquid chromatography-mass spectrometric methods (HPLC-MS). More recently researchers in Finland have successfully generated monoclonal antibodies to PEth and have demonstrated a laboratory based fluorescent PEth assay and FACS analysis of human red blood cell samples spiked with PEth. This laboratory-based method still requires expensive instrumentation and skilled personnel to perform the analysis. Unavailability of rapid assays for the detection and the lack of standardization of the tests have hampered the clinical use of these biomarkers. To overcome the limitation of expensive instrumentation in PEth analysis we propose to develop and demonstrate the feasibility of a low-cost, onsite assay for PEth using a monoclonal antibody based electrochemical immunosensor technology.